Magnesium Supplementation Dosing

What Type of Magnesium supplement should I take?

Each of the following Mg salts contain two parts: the ionized Mg and the carrier component, which may be light weighted like chlorine or heavy like the organic compound like gluconate. The amount of magnesium (the active ionic Mg component of the salt) is stated just after the name of the salt. Everyone must know the amount of elemental Mg they take. This is the best way for us to communicate, such as the amount one needs. Be sure to remember the amount of elemental Mg you are taking, which is found in your Mg salt. All of these Mg salts are over the counter (OTC) products, although the brand may not be stocked in all drug stores, so check with the pharmist to learn if it is behind the counter or can be ordered. We usually recommend only the four numbered (1-4) salts below that are printed in bold.

The following shows the amount of el. Mg per dose of the Mg salt, also stated is the percent (%) of el. Mg in the salt.

I. Magnesium preparations available

  • Magnesium chloride (MgCl) is: 128 mg (5.2 mEq) elemental magnesium (el.Mg) per 2 tablets. The salt MgCl contains 25.5% Mg. Slo-Mag is a MgCl salt oral tablet that contains 64 mg of el.Mg, it is coated so it passed thru the stomach before it is absorbed, which peaks in 3-4 hours. This salt is also used intravenously and I believe it is safer than magnesium sulfate (MgSO4), see below. While we can not use the product IM as available in the USA, it might prove to be less painful than MgSO4.
  • Magnesium citrate (MgCit) is: 160 mg/1,000mg tablet (4.4 mEq) of elemental magnesium. The solution of Citrate of Magnesia contains 3.26 grams of elemental Mg per 10 ounce (300 ml) dose. The salt MgCit contains 16.2% Mg. At a dose of 607 mg of Mg MgCit is 9 times more soluble than MgO and is used for kidney stones for that reason. (Lindberg, JS, J Am Col Nutr 1990;48-55). This data suggests that MgCit might work as fast as MgG, see below.
  • 1A. Magnesium gluconate (MgG) is “Magonate”: 27 mg (2.25 mEq) elemental magnesium. The salt MgG contains 5.9% Mg.
  • Magnesium hydroxide, “Milk of Magnesia”, contains 498 mg of elemental Mg per 15 ml (1/2 ounce). Mg poorly absorbed in this catheretic dose.
  • 2A. Magnesium-L-aspartate HCl (MgA-HCl) is “Maginex”: 61 mg (5 mEq) elemental magnesium. (The salt MgA-HCl contains an unknown % of Mg). DO NOT use Magnesium aspartate unless only option, since less well absorbed.
  • 3A. Magnesium lactate (MgL) is “Mag-Tab SR” : 84 mg (7 mEq) elemental magnesium. The salt MgL contains 12% Mg.
  • 4A. “Magnesium oxide” (MgO) is: 603 mg (49.6 mEq) per gram of elemental magnesium. The salt MgO contains 60.3% Mg. Amount of MgO per pill varies with each company, see below.
  • Magnesium sulfate (MgSO4) molecules contain 10% elemental magnesium. Epson Salts is an old laxative, that could be used if necessary, A dose of one ml of a 50% solution of magnesium sulfate intramuscularly, some add lidocaine for pain. Adult intravenous or via Implanted Port the dose is: 1-2 g (2-4 ml of a 50% solution) in 10 ml of D5W over several minutes IV; for example, administer IV push in VF at the rate not to exceed 150 mg per minute. The maximum dosage of MgSO4 is 20 grams per 48 infusion of 0.2 mEq (2.4 mg) of Mg per kg of lean body weight given in 5% Dextrose in water over 4 hour, to be used for maximum retention once acute symptoms are controlled (Ryzen, E., Magnesium,1985,4:137-147). (NOTE in most patients it is best not to use any saline solution, it increases Mg renal loss {Massry, S.G. Am .J.Phyysiol, 1967,213:218-224}) , For example should be used to correct the intracellular MgD associated with prolonged QT interval over several days. Another option would be intraperitoneally. (Bahar, B Nephrol Dial Transplant 2001; 16: 2086-2089). contains 1 gram of MgSO4 or 49.3 mg of el. Mg (4 mEq). A 1-2 gram dose is used Remember the longest lasting dose is
  • How to added Mg SALTS our Treatments

4B. MAGNESIUM OXIDE is an intermediate acting salt. We have assayed Blaine MagOx 400, (contains 240 mg of elemental Mg per tablet) and content is as stated. It is also free of lead, mercury, cadmium, arsenic and aluminum; and it is free of chemical solvent residue, herbicide, pesticide, and fungicide residue. This product is the most widely used and available Mg product recommended by USA physicians, often even by prescription, although it is OTC. NOTE: this product is covered by Medicaid programs in most USA states.

General Nutrition Center (GNC) Mg oxide products were found by our assay to be accurate as stated on their labels. Other cheaper less know and less studied brands of Mg oxide also are available.

Start With This salt, once on 3-4 tablets of Blaine MagO 400 mg, every 4-6 hours, per day or develops diarrhea, one should then add other salts beginning with Mag-Tab SR and then Maginex.

It is obvious from the above list that Mg oxide (MgO) is the workhorse because it contains the highest concentration of Mg. Actually 60.3% of the MgO salt is elemental Mg, the part that counts. That is its major advantage, but it might be too much for some patients. A disadvantage is that it takes about 2 hours for any to be found in the urine. This is the only sign of absorption of Mg for those with normal sMg levels, which is also the amount of time it takes to see any clinical effectiveness to be seen. The MgO peak effect is in 4 hours, and gradually decreases in a few hours. Even with very high doses the kidneys will only maintain your sMg levels in the normal range, since Mg is stored in the bones not the serum.. If one’s sMg is below normal, the sMg level will ultimately increase to the normal range. Thus between 0 and 2 hours, and between 4 and 8 hours the patient may need a higher dose to prevent symptoms of MgD.

1B. MAGONATE is a rapid acting salt. (A Mg Gluconate (MgG) salt, (there are 2 molecules of G in this salt, to one atom of Mg) is made by Fleming and Company Pharmaceutical; our research laboratory assay has found the content to be accurately stated). MgG contains only 5.39% Mg.

MgG is well tolerated, which is very important when taking any Mg product for the first time. Your druggist will usually have to order it. It takes only one day and does not require a prescription. Order 3 bottles of 100 tablets, which is enough for 2-4 weeks, a minimum trial.

Each 500 mg tablet contains 27 mg of Mg*, and 5 tablets equal 135 mg of Mg. This means that 5.8% of the MgG salt is elemental Mg, which is the active component of all of the Mg salts. It is very rapidly absorbed, and the peak effect occurs in less than an hour when taken on an empty stomach, and within an hour from the stomach even when needed after food This Mg salt enters the blood and then the cells through the glucose pathways in the stomach. The salt then dissociates in the cells to free gluconate and functional free ionized Mg. (FDA PB-288 p675 and p537). While other Mg salts, which take 2-4 hours to get their peak effect, MgG’s down side is that it is such a small amount of Mg that one needs at least 5 pills or as much as 10 tablets (270 mg of Mg) every half hour for 2-3 hours. It is wonderful for migraine, as soon as one feels the aura. It usually needs to be used with Mg oxide (MgO), if high doses of Mg are needed.

This Mg salt is an excellent RESCUE product, because five to ten tablets often relieves sudden unexpected acute symptoms (like muscle pain/cramps, PMS and burning feet) and can be repeated as soon as one-half hour later 2-4 times without resulting in diarrhea. It has been shown that IV MgSO4 relieves Migraine (Mauskop, Headache. 1996:36;154-160) and Magonate by mouth does the same thing. Many need 10 tablets every half hour for 3-4 times to prevent a migraine attack after the aura or actual headache occurs. Some of the daily dose of this salt is best taken at bedtime, because it results in a rapid sound sleep due to muscular relaxation. Also, I have used it this way for acute onset of Atrial Fibrillation.

* Since this product contains 89 mg Calcium as Ca Phosphate per tablet, a poorly absorbed Ca salt, and no vitamin D (which facilitated Ca absorption), be sure to count at least half of the amount of Ca taken from these pills in your daily Ca allowance.

3B. Mag Tab SR is a delayed acting salt. (This Mg salt is made by Niche Pharmaceutical Inc., 800-677-0355.

Mag Tab SR is 84 mg of Mg from Mg L-lactate (MgL) in caplets containing a sustained release wax matrix formulation of this dehydrated compound. This formulation has the theoretical advantage that Mg is absorbed in small increments, 7 mg/hour for 12 hours as the matrix moves through out the bowel. It has been shown that lactate is excreted in the urine after taking MgL, which means that it is mostly absorbed intact leaving little or no Mg in the bowel to bind with 300 times it’s weight of water, thus less likely resulting in loose stools.

2B. MAGINEX is an intermediate release enteric-coated Mg salt from Geist Pharmaceuticals 1-888-644-3478.

Maginex is a 61 mg of Mg from Mg-L-Aspartate HCl in an enteric-coated tablet, to bypass the stomach. Its Mg levels peak in 3-4 hours, judged by urinary excretion and measurable, statistically significant, serum levels (10% increases) in 4 hours. Total absorption is 50% more than Mg from Mg Oxide, reported in the medical literature. (Muhlbauer B, Eur J Clin Pharmcol, 1991;437-438). It is important to use the HCl salt, since the neutral acid protects the ability to absorb iron.

Maginex DS, is a packet of the same salt of Mg, which contains 122 mg of elemental Mg in a soluble powder to be added to juice or water. It has a lemon flavor. Usual starting dose in 6 mg/kilo per day in 4-6 equally divided doses in infants and children.

Magnesium Citrate is an intermediate acting Mg salt, its major advantages are that the Mg from magnesium citrate is more soluble and bioavailable than from Mg oxide and it is probably the cheapest of all of the salts as Citrate of Magnesia, sold as a cathartic. (Lindberg JS in J Am Col Nutr. 9(1):48-55, 1990). But when given in the form of a blood infusion product, it causes an acute and steep drop in serum ionized magnesium. (Mercan D, in Transfusion. 37(4):418-22, 1997). The same thing happens to serum ionized Calcium resulting in symptoms of CaD. (Bolan CD. Transfusion. 41(9):1165-71, 2001) Therefore one may need more Mg compared to the Mg from other Mg salts. It should not be taken with any aluminum containing antacid, since the citric acid in orange juice results in the absorption of aluminum, so it is possible that this Mg salt would do the same thing. (Fairweather-Taut S. in Euro J of Cl Nutr. 48(1):71-3, 1994). Unfortunately I have not been able to find the amount of Mg in Citrate of Magnesia, therefore I would start with 5 drops 3-4 times a day and slowly work up the amount to The Maximum Tolerated Dose (MTD), which is soft semi-solid stools. Mg appears to be 16% 0f the molecule containing 3 Mg ions and 2 citrate molecules or 162 mg of Mg per 1,000 mg (1 gram) of the salt, Mg citrate. (See Life Extension Foundation Magnesium Citrate at the following link.) 

More Than One Salt at a Time In certain situations all three types of these four marked Mg salts: an immediate, an intermediated, and the delayed acting Mg salts, may be necessary to reach one’s maximum tolerated dose without peaks and valleys, and that is without symptoms during the low periods, (valleys). They should be taken together.


General Principles

1. All adults, even with Bartter’s, Gitelman’s and Distal Renal Tubule Acidosis, should be drinking at least eight 8-ounce glasses of fluid, mostly water, per day.

2. All Mg salts are better tolerated with at least a 100-calorie snack.

3. For its most rapid action, Magonate is best taken on an empty stomach, one hour before or two hours after food intake. Yet it works with food.

4. Because of Magonate’s rapid onset of effect it can be taken with another Mg salt for sudden unexpected acute symptoms, like migraine aura, migraine, muscle cramps, PMS and burning pain. Count the extra Mg as part of the daily total.

5. The total daily dose should always be taken in equally divided doses, 2-6 times a day (12-4 hours apart) and at equally divided times..

6. Always start with the smallest available amount, ½ a tablet, as far apart as possible, initially every 12 hours.

7. Always error by taking more at nigh, ½ at 10 AM and ½ at 10 PM, then ½ +1, 1+1, 1+1 ½, 2+2, 2+2 ½ etc.

8. Increase dose slowly every 1-2 days, when 2+2, go to 2+1+2 every 8 hours, etc.

9. Learn the amount of elemental Mg in each salt, so that once on 4 pills of Mag-Tab SR, or 10 of Magonate you might try substituting 1-250 mg (or 240 mg) tablet of Mg Oxide. It saves your doctor’s time if you know you elemental Mg amount taken per day.

10. The idea is to slowly increase the dose up to the point of producing soft semi-formed bowel movements without diarrhea-your MTD.

11. When changing Mg salts or to a different brand it is best to gradually make substitutions by alternating sources.

12. A word of caution: the clinical effect all Mg salts is decreased by the simultaneous taking of many drugs. Neurontin is an example, 24% (in the PDR) is not absorbed when taken with Mg, moreover those controlled with a given Neurontin dose find they need more, because of this Mg binding in the blood. This is managed by increasing both the Mg and the Neurontin to remain controlled and symptom free be it due to MgD or due to Neurontin.

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